Radio loud-speaker construction



March 12, 1929.

J. KERSTEN RADIO LOUD SPEAKER CONSTRUCTION 2 Sheets-Sheet 1 Filed March 28, 1927 Jooob Patented Mar. 12, 1929.

UNITED STATES JACOB KIRSTEN, OF KALAIAZOO, MICHIGAN.

mmo LOUD-SPEAKER cons'rnuc'rlon.

Application filed March 28', 1927. Serial Io. 178,852

This invention relates to a radio loud speaker construction and is particularly concerned with the housing which encloses an amplifying horn to which the loud speaker unit is connected. The invention is directed to the structure of the housing and the method followed in producing the two parts or halves of said housing.

It is a primary object and purpose of the present invention to provide a-housing for amplifying horns made of paper and papier mach, and to strengthen and reinforce the same so that it will be durable in service and so that one side or half of the housing may be provided with a'large number of openings through which the sound escapes without fear of the parts left between said openings breaking or disintegrating. More specifically the housing members made of paper and papier mach are reinforced around their edges by embedded wire rings and are reinforced at their outer sides by fabric cemented thereon, which fabric greatly strengthens the housing parts and makes it possible to saw desired openings in accordance with any particular design without the material'breaking or crumbling, while said fabric at the outer side of the housing mem hers is particularly useful in the application and retention of a finish for said housing.

To these ends as well as many others, I have made the invention and have devised a practical method for the same, understanding of which will be had from the following description taken in connection with the ac companying drawings, in which Fig. l is a front elevation of the complete assembled housing. i Fig. 2 is a central vertical section therethrough.

Fig. 3 is a vertical section through the mould used in constructing each of the halves y or parts of the housing.

Figs. 4, 5 and 6 are fragmentary enlarged vertical sections illustrating different steps of the method followed in constructing each housing part, .and Fig. '7 is a fragmentary vertical section showing the application of the fabric outer member to each housing part after it has been removed from the mould.

Like reference. characters refer to like parts in the different figures of the drawings. The mould used comprises a block 1 in the upper side of which a large conical recess or depression 2 is made which at its upper edges joins with a vertical ledge 3 made in the moulding block 1. This ledge is of comparatively shallow depth and is set inward from the outer edges of the block so that a horizontal face i is provided at the upper side of the block outside of the ledge 3.

In the mould thus formed each half of the housing is made. In the fir'stinstance two sheets of paper 5 and 6 are laid in the mould and are fitted to the ledge 3 and extend outwardly over the face 4: of the mould. These sheets of paper in practice are known as rosin paper and are cemented together by a suitable glue paste. After the two sheets 5 and 6 have been laid in the mould, as shown in Fig. 4, a circular ring 7 made of wire is laid in the mould and it is of such size that it engages against the sheet 6 of the paper directly opposite the ledge 3.

The succeeding step of the method followed is to lay in and cement two sheets 8 and 9. of papier mach. These sheets are thicker than the rosin sheets 5 and 6 used and are less tough and porous. The sheets 8 and 9 when cemented in place have their edges coming to the inner sides of the wire ring 7 and are thick enough that the twotogether are substantially equal to the diameter of the wire used.

The final step of the method followed in the mould is to cement two additional sheets 10 and 11 of tough rosin paper above the sheet 9 of papier mach, the same extending from the mould and dried afterwhich a piece of knitted fabric- 12 is stretched over the outer side of the housing member formed, as shown in Fig. 7, being glued to the outer sheet of paper 5 which was the first sheet laid in the mould. The fabric adds considerable strength to the structure made, and particularly it prevents breaking I of the edges when the housing parts are subjected tosawingoperations as will now be described. 7

When each half of the-housing has been completed asdescribed it consists of a com cal body lei ifrom which an annular lip 15 projects. Both parts ofwthe housing are sawed so as to remove the rough edges of the lips 15. The 'two' halves of the housare joined together by a tubular ring 16 slotted at its inner side which clampsv against the abutting lips of the housing,

as shown in Fig. 2. Ringv 16 is continuously around the housing except at the lower side 15;-

of'the' housing are sawedaway to leave an where there is a gap, and certain'portions opening 17 through which the lower end or neck of the amplifying horn passes. The front side of the housing is sawed on a band saw so as to make a large" number of openings 18 which are cut'to make any suitable artistic design. Without the fabric covering 12 it would be impossible to out these an'd covered at .its outer openings 18 for the reason that the narrow portions left between the openings would be too weak, would easily break and particularly at the edges, would crumble. But by I use of the fabric outer side such crumbling and breaking iscompletel eliminated.

In addition, the outer side of both parts ofthe housing necessarily must be finished to present a good appearance and the fabric stretched over the outer sides of said hous ing parts is especially effective to receive and retain a-filler, varnish or other finish which may be applied. a I

The constructlon of the arts of an amplifying horn housing descri ed and the method followed is one which has proved very useful and practical. It results in economy sides with abric cemented thereto.

2. In a housing member for use in producing a housing to enclose'an amplifying horn comprising, a conical shaped body avmg'an annular lip extending outwardly from the edges of said body, said body and lip being formed of fm'ented to. t ,lip. g I 3. Ariarticle of manufacture comprising,-

aper material, and fabric ceaper e outer'sideof said-body and I and substantially of a thickness diameter of'the ring and then laying strataan integral a conical shaped the havinlgl t e base edges annular li extending from of said he y, and a wire rin embedded in said article substantially at t the bodyand lip..

e juncture of 4'. An article of manufacture comprising, .aconical shaped body having an annular 11p.

projecting from the base edges vthereof, said body including at its inner side sheets of paper cementedtogether and extending outwardly to the outer edges of said lip, papier mach located over and cemented to the inner of said paper sheets extending substantially to the juncture of the lip and body,- a wire ring located around the edges of said papier 'mach and additional thicknesses of paper cemented o er said papi'er mach and extending over and beyond sa1d r1ng and cemented to the first mentioned sheets of paper to make said lip.

in combination defined in claim 4:, and a covering of stretchable fabric stretched over the outer side of the body and lip cemented thereto and extending to the edges of said lip.

6. An article ofthe class described comprising, a conical body havin an annular lip projecting from the base e ges of said body,

said body comprising inner and outer stratav of relatively tough paper, said strata extending to the edges of'said lip and being cemented together, an inner filler of papier mach or the like extending substantially to the juncture of said body and lip, and a metal reinforcing ring disposed between the outer and inner strata of tough paper and around the edges of said stantially as described. 1

7. A housing for amplifying horns cominner filler, subprising, two members, each forming a half of the housing and each being of recessed form having their base edges located against each other and secured together, each of said members at its lower side having a portion cut away to make an opening in the lower side of the housing and one side of said therethrough" in accordance with any preferred design, each of said members having an'finner body. of paper material and an outer covering of elastic fabric stretched over and cemented to the same.

8. The method of manufacturing a housing member for an amplifying horn which consists providing a recessed mould, fitting inner strata of tough aper into said mould and extending the e ges thereof beyond the edges of said depression, laying a housing having a plurality of openings cut I 85' 5. Aconstruction containing the elements of tough paper over said filler and over said ring and extending the edges to overlap the edge portions of the first strata, and cementing all of the paper strata and material together.

9. The process of manufacture which consists of the steps defined in claim 8 and further in removing the article formed from the mould, drying the same and then cementing an outer covering of stretchable fabric against the first sheet of paper placed in the mould, drawing and stretching the fabric over the article with its edges extending to the edges of said first paper sheet.

In testimony whereof I afiix my signature.

JACOB KERSTEN. 

